Gee, I thought the only thing the Temp I sender did was send a signal to the
gauge.  Well, I'll be dipped in Orange Coolant!

DM&FS
----- Original Message -----
From: "Mark Keller" <kelphoto@islandnet.com>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, May 11, 2001 10:39 AM
Subject: Re: Gas Mileage and Fuel Pressure Regulator

> Listmembers,
>
> I wrotee about the Temp I sensor below in two previous post.  After
> re-reading my original post I would like to clarify that the Temp I
> sensor only indicates an "extra rich mixture by say 20% on extremely
> cold mornings, say when the temperature is <32 F or 0 C.  The TEMP II
> sensor Cold start enrichment is for general conditions.  I had
> originally wrote to this effect and mistakenly deleted it  during an
> edit.  Sorry for any confusion.
>
>
> To add to the discussion regarding Temp I function on the Digifant
> system during my original post:
>
>
> The information I received from Darrel Boehler was that that extra fuel
> enrichment is added by the ECU when the TEMP I sensor indicates near
> freezing air. The ECU's map may then wait until either an indication
> from TEMP II, i.e. engine beginning to warm, or just wait until close
> loop before the TEMP I enrichment value is canceled out.
>
>   Either way, Darrel "guestimated" the value to be 20% extra to the
> regular cold start mixture map. It seems Darrel stated that this is the
> only purpose for the TEMP I sensor.
>
>
> My original post excerpted below is:
>
> "The first clue that the fuel pressure regulator is setting too high a
> pressure is cold mornings when temp I, an air temp sensor, determines if
> the computer richness the mixture to start the engine.  A pressure
> regulator that is beginning to get too high will cause the engine to
> sound like it's running on three cylinders, or chug, and then as it
> warms up and the Temp I compensation is removed, the chugging smoothes
> out.  I've had this, and was related  too high a fuel pressure."
>
> Sincerely,
>
> Mark Keller
> 91 Carat
> Cowichan Bay, BC